I don't want her to lie or believe falsehoods, but I cannot just say "it's a lie most adults tell children" (yet). Aside from her ability to understand such a complicated statement, there are other, very catholic, children in the family. Children, who got two cardboard versions of the Bible for their second birthday (because the first one was still too advanced). I think the "fairy-tale of Claus" does this quite well.

The thing is all of the other takes on this topic start from a point, when a child (usually 5-9 years old) asks "Is Santa real?" Nobody yet asked "how to raise my child Santa-free?" What to say, when a two-year-old, who just noticed that there is this character on TV asks "will he come to me, too?" A toddler may not yet understand the concept of lie, of pretending, of things not physically existing. (I think I'll just add this part to the post)